Sunday, 4 September 2016

My internet research frequently involves trawling through old patent documents. These often provide a wealth of information, and I'd like to share some of this with you now. Great Britain patent 376,974 was applied for in August 1931 by the Swiss engineering firm Brown Boveri. Granted in August 1932, it has as it's object "Improvements in and Relating to Combustion Chambers".This is one of the earliest references I can find depicting a combustion chamber made from tubular elements to allow a coolant to be circulated through.Whilst the invention described was intended for the production of power, not thrust, it is easy to see where the concept of a tube bundle thrust chamber may have originated.It is highly instructive to quote directly from the patent document itself:-

Reading further we find:-

This is exactly what I am trying to achieve. Some of the drawings accompanying the application are strikingly similar to my own sketches, and the constructions shown are mirrored closely by my earlier tube welding trials:-

The document also describes the use of bands of material welded around the tube bundle to take the hoop stress caused by the combustion pressure. All of this information will go in to the pot and add to the tube bundle design effort.

About this blog

This blog describes the research, design and construction of a Liquid Rocket Engine.
As such it will include information regarding the design and construction of rocket engine components.
This will encompass theoretical and performance concerns, as well as machining, welding and manufacturing techniques used to overcome the various problems encountered.
In addition, my interests in this direction include control and data acquisition. So there will be posts regarding electronic systems and microcontrollers.
It is my hope that as well as being of interest to the rocket engine community, it should also become a repository of general amateur engineering information.
I was inspired to create a blog by the groundswell of interest that I have had in my project from people I have met. I have found that their reactions tend to go from perplexity to enthusiasm rapidly! The main question most people have is not to do with the technical obstacle to be overcome. Most of those who have asked me about my project have wanted to know "Why are you doing this?" So I will try to give some answers to this and to explore my motivation to think, research, create and construct.